Comparison of techniques for estimating nutrient intake: the Framingham Study.

We compared estimates of nutrient intake by three diet assessment methods (24-hour recall, 3-day food record, food frequency questionnaire) in a random sample of 73 females and 77 males from the Framingham Offspring/Spouse Study. The results differed according to analytic method. Estimates of group mean intake from the 24-hour recall and 3-day records were similar in both women and men, with differences of less than 10% for most nutrients. The estimates of mean intake calculated from the food frequency questionnaire generally differed from those obtained by the other methods, with higher estimated intakes in women and generally lower estimated intakes in men. Spearman rank correlations between the individuals' nutrient intakes estimated by the three diet assessment methods were modest (r = 0.08-0.68, most below 0.50) and comparable in the comparisons of the 24-hour recall or food frequency questionnaire with the 3-day records. Our data suggest the interchangeability of the recall and record methods and their preference over the food frequency questionnaire for mean estimates of group nutrient intake. The food frequency questionnaire appears to be of some utility in ranking individuals according to the usual intake, although these data are not informative in comparing this method with multiple days of recall or records beyond 3 days. This research underscores the need to develop and evaluate short methods of diet assessment in specific populations of interest.